Hydraulic sizer for suspended solids



Nov. 15, 1955 G. M. DARBY HYDRAULIC SIZER FOR SUSPENDED SOLIDS 9Sheets-Sheet 1 Filed July 23, 1952 r. w n 0. D I

George M. Darby orneg Nov. 15, 1955 G. M. DARBY HYDRAULIC SIZER FORSUSPENDED SOLIDS 9 Sheets-Sheet 2 Filed July 23, 1952 ZSnventor GeorgeM. Derby 4): totneg Nov. 15, 1955 s. M. DARBY HYDRAULIC SIZER FORSUSPENDED SOLIDS 9 Sheets-Sheet 3 Filed July 23, 1952 Snventor George M.Darby ttorfieg Nov. 15, 1955 G. M. DARBY 2,723,754

HYDRAULIC SIZER FOR SUSPENDED SOLIDS Filed July 25, 1952 9 Sheets-Sheet4 5 Fig. 4.

38 33 38 A L 1 T if; I'mventor George M. Darby /0 i 4 J ax Nov. 15, 1955G. M. DARBY 2,723,754

HYDRAULIC SIZER FOR SUSPENDED SOLIDS Filed July 23, 1952 9 Sheets-Sheet5 Ii 25" s) Illlll lu 7 9 /29" INVENTOR George M. Darby ATTORNEY Nov.15, 1955 Filed July 23, 1952 G. M. DARBY HYDRAULIC SIZER FOR SUSPENDEDSOLIDS 9 Sheets-Sheet 6 3nventor George M. Darby attomcg 7 Nov. 15, 1955Filed July 23, 1952 Fig. 7

G. M. DARBY HYDRAULIC SIZER FOR SUSPENDED SOLIDS 9 Sheets-Sheet 73nventor George M. Dorby uiw x (Ittomeg Nov. 15, 1955 s. M. DARBY2,723,754

HYDRAULIC SIZER FOR SUSPENDED SOLIDS Filed July 25, 1952 9 Sheets-Sheet9 Imnentor George M. Darby J e 2 1D 0 tomeg United States Patent 12,723,754 HYDRAULIC SIZER FOR SUSPENDED SOLIDS George M. Darby,Westport, Conn.', assignor to Dorr- Oliver Incorporated, a corporationof Delaware Application July 23, 1952, Serial No. 300,559 6 Claims. (Cl.209-461) This invention relates to apparatus for hydraulically sizing orclassifying a mixture of solids into a sequence of size fractions orgroup of sizes, the first to contain a range of the largest sizes, withthe following groups or fractions each to contain a range of sizessmaller than those in the range of the preceding group or fraction.

More particularly, this relates to hydraulic sizers of the hinderedsettling type the general operating principle of which is represented inand by the well-known Fahrenwald sizer as shown for example in BritishPatent No. 268,663 with filing date of October 4, 1926.

In classifying or sizing apparatus that operates on the hinderedsettling principle the sizing or solids fractionation of a slurrycontaining the mixture into a desired fraction of coarse solids and adesired fraction of finer solids is eflected as the mixture of suspendedsolids feeds into and passes across a pool or pocket or vertical columnof liquid from the bottom of which rises a cross-sectionally uniformstream of pressure water which is the so-called hydraulic operatingwater or simply hydraulic water. In order to attain a desired sizefractionation, the quantity and upflow rate of this hydraulic water mustbe established in relation to certain other operating factors, namelythe density of a teeter bed of suspended solids to be maintainedconstantly in the column, the rate of coarse solids discharge (spigotdischarge) from the bottom of the teeter bed, and the rate of slurryfeed to the column. That is to say, by the setting of the upflow rate ofthe hydraulic water and by maintaining the proper density of the teeterbed in the column through the constant control of the rate of the coarsesolids discharge from the bottom spigot, this type of apparatus permitsrelatively sharply controllable classification of the slurry mixtureinto a coarse spigot fraction of a desired size range and an overflowfraction of fines of another desired range. In other words, thecharacter of the fractions, namely of the coarse spigots discharge andof the fines overflow, from such a hindered settling column isdetermined and depends upon the accuracy of control of the density ofthe teeter bed against the upflow of the hydraulic water, devices forsuch control being well known and provided in the form of a liftablevalve member seated in the spigot discharge opening in the bottom of thecolumn, together with automatic devices for correctively positioning thevalve member in such a manner as to compensate for any deviations fromthe desired state of density of the teeter bed by a correspondingincrease or decrease of the coarse solids spigot discharge.

As embodied in the early Fahrenwald sizer or in any of its later andmore recent improvements (such as patent to Haagensen, No. 2,371,615 ofMarch 20, 1945; patent to Darby, No. 2,410,637 of November 5, 1946; andpatent to McKay, No. 2,425,551 of August 12, 1947) the type of apparatusherein considered represents a multiplespigot, hindered settlingclassifier which, from a feed suspension mixed with respect to particlesizes, produces closely sized spigot products along with an overflowcarrying fines.

Such a multiple spigot apparatus comprises a sequence or horizontal rowof teeter bed columns with the slurry to be classified entering at oneend, passing sequentially over these columns or pockets while leavingbehind in each pocket the respective hydraulically controlled andselectively intercepted size fraction, with a final fines fractionescaping with the liquid overflowing at the other end. Thus the desiredsolids fractions are abstracted sequentially from the horizontal streamof slurry passing through the apparatus by way of the respective teetercolumns or classifying pockets of this apparatus and these fractions aredelivered as the respective spigot product therefrom.

This invention is an improvement upon and over the classical Fahrenwaldform of multi-pocket hindered settling sizing apparatus, which form inprinciple has maintained itself up to date even though improved withrespect to certain control accessories such automatic density controlmechanism disclosed in some of the abovementioned patents.

This invention then can be said to provide an improvement over astructure which is known to comprise a longitudinal tank with verticalside walls diverging somewhat from end to end of the tank and havingtransverse submerged vertical partitions dividing the tank into ahorizontal sequence of classifying or sizing pockets or columnstrapezoidal in plan view, with the spacing between the partitionsincreasing towards the wider end of the tank whereby in plan view areathe pockets increase towards the Wider end of the tank. The mixed solidssuspension or feed slurry enters the narrow end of the tank continuouslyWhile liquid carrying the residual fines overflows a weir defining theliquid level above the partitions in the tank, even as the various sizeranges of the solids received by respective pockets dischargecontinuously from respective spigots as sized products.

In such conventional apparatus the character of the size portions asdelivered by respective spigots is controlled by hydraulic Watersupplied to a hydraulic feed chamber provided directly underneath eachrespective teeter column and rising through a constricton plate orperforated member constituting the bottom boundary of the teeter columnproper. In such apparatus there is provided the usual vertical andcentrally disposed spigot discharge duct for each teeter column orpocket which duct extends through the hydraulic feed chamber presentinga central dischargeopening in the constriction plate and constitutingtherein a valve seat for a conventional conical valve member or plug.The valve member has a vertical stem extending upwardly into connectionwith an automatic control unit disposed at the top of the tank for eachpocket and whereby the valve member is correctively raised or loweredwith respect to its seat for correctively varying the spigot dischargerate individually of each teeter pocket. The operation of each densitycontrol unit is governed by variations in the density occurring in eachrespective teeter bed, inasmuch as the control unit responds to densityvariations by way of a clear water column that communicates withthebottom strata of the teeter bed. Thus any increase or decrease indensity will produce a corresponding degree of rise or fall of the clearwater column which rise or fall in turn acts upon the control unit toproduce proportionate corrective control effects in terms of raising orlowering the valve member relative to its seat, so that a density closeto a desired value is correctively maintainable in the teeter bed.Examples of density control devices thus governed by variations of aclear water column are shown in the above-mentioned patents toHaagensen, No. 2,371,615 and McKay, No. 2,425,551.

Such conventional multiple pocket classification units especially ifequipped with automatic density control are ideally suited to meetcertain requirements for accurate size control, for example in treatmentof slurries where particle difference of micron accuracy may beimportant as in the sizing of abrasives. Yet, the present day apparatusof this type may be said to have reached a unit capacity limit in viewof the fact that even with the use of automatic density control devicesa uniform density becomes more difiicult to attain and to maintain with3 any increase in area of the respective pockets served by therespective spigot discharge control devices.

Moreover, the conventional hydraulic multiple pocket sizing unitdepends. for its proper operation. and for the attainment of thedesired-sizing effects upon the provision for each pocket of the propertype of constriction plate, namely a plate having the number and size aswell as spacing of the holes best suited to bring about the desiredefi'ects. Hence, to inspect these constriction plates for wear or otherreasons or to change such plates for operational reasons, has requ rednot only the shutdown of the operation, but also the dismantling of thebottom sections or hydraulic chambers. as well as of the water supplyconnections for these chambers with attendant protraction of theshutdown.

As regards capacity and other operational characteristics these arenotreadily predictable for the conventional apparatus especially for anyprojected increase of size andcapacity, hence design data for aprojected capacity machine are not readily arrived at due to uncertaintyor unpredictability of performance characteristics, where capacitychanges especially increases over present day capacities arecontemplated.

At any rate, the present day multiple pocket multiple spigot hydraulicsizing apparatus of the hindered settling type may be said to havereached the limits of its structural size inasmuch as further increaseof apparatus size for the purpose of increasing the total capacity wouldtend to make the apparatus structurally relatively less economical whilerendering it relatively less efficient or accurate or selective withrespect to desired particle sizing results.

It is among the objects of this invention to provide a multiple pocketmultiple spigot hydraulic sizer unit with the capacity to handle liquidvolumes along with quantities of solids far beyond present day capacitylimitations, yet without sacrificing controllability of densityconditions in the respective hindered settling pockets and withoutsacrificing acccuracy of size fractionation. Indeed, it is among theobjects to provide a supersize high capacity unit that is readily anduniformly controllable as to density condition in all its areas andpossesses exceptionally well controllable particle size selectivity andhigh fractionation accuracy in the sense that each fraction or spigotdischarge contains a minimum of tramp sizes or of sizes. contained inthe spigot discharge of an adjoining pocket, and yet, which supersizeunit is relatively cheaper to construct and will by comparison requiremuch less shutdown time if any, and which will. avoid opera tional-,design-, and constructional-problems encountered with the use of theconventional constriction plates.

Indeed it is among the objects to provide distributing means whereby auniform and uniformly controllable upfiow of hydraulic. water isprovided in each pocket area without necessitating the use ofconstriction plates; such distributing means to be readily inspectableand exchangeable without requiring any of the cumbersome dismantlingheretofore necessary, so that labor and the duration of the shutdown maybe minimized.

These objects are attained by way of a new concept according to whichthe apparatus unit or multiple spigot tank is visualized in plan view asa combination of cooperatively associated columnar component volumesdefinable by a system or combination of submerged transverse andlongitudinal vertical partitions which constitute the boundaries oftransverse. rows. of columnar cells, of substantially identical squarecross-section. Each such cell is to hold 'a teeter bed of individuallycontrollable density, with the solids-carrying liquid passing above thissystem of partitions and teeter beds in a direction from the narrow endto the wide end of the tank. Moreover, each of these columnar cells orteeter beds is equipped with its own automatic density control devices,namely a spigot outlet valve with individual automatic control unittherefor.

Hydraulic water is controllably supplied to each transverse row ofcolumnar cells or teeter beds not through conventional constrictionplates, but is introduced from an overhead horizontal pipe system by wayof a depending system of jet-emitting distributing pipes. That is tosay, vertical branch pipes extend from the overhead pipe systemdownwardly into each columnar cell or teeter bed and they connect withhorizontal jet-emitting pipes. The jet-emitting pipes for each cell aresupported upon and spaced a predetermined distance from the solidnonperforated square tank bottom portion of the cell which has thevalved spigot outlet in the center. Indeed, each such basic, square cellmay thus be provided with a substantially identical system of horizontaljet-emitting parallel pipes, the pipes being so placed from one anotherand from the boundaries of the cell, and the jet-emitting orifices inthese pipes being so arranged and dimensioned and so disposed withrespect to one another that there results from such arrangement in eachcell an upflow of hydraulic water from the bottom which upfiow issubstantially uniform and uniformly controllable across the area of theteeter bed or cell, and adapted to sustain a teeter bed of desireddensity.

According to this invention then, the apparatus or tank presents itselfas a combination or honey-comb-like system of basic square cell units orteeter beds of equal predetermined size, each with its individual spigotdischargev and automatic density control and with a substantiallyidentical jet-emitting pipe system for hydraulic water supply, so thatthe apparatus may be said to represent the employment of a multitude ofthe basic cells each complete with control devices and overheadhydraulic water supply, in such a manner that a single such cellconstitutes the narrow end of the tank while a plurality of such cellsin a transverse row constitutes the wide end of the tank. Thus a planview of the tank presents a characteristic configuration namely withsides which are stepped from the narrow end to the wide end of the tank.Indeed, the total area presents itself as a sequence of rectangularareas or transverse sizing zones of stepwise increased width, each ofwhich zones comprise one or more transverse rows of the submerged squarecells; each rectangular area or transverse zone is larger than thepreceding one upstream, whereby there results the above-mentionedstepped configuration of the tank.

Such stepped configuration simplifies design as well as fabrication ofthe tank inasmuch as it confines all structural wall area components ofthe tank to simple rectangular shapes of readily determinable size.Moreover, importantly fora supersize tank made possible by thisinvention this stepped configuration presents the opportunity ofconveniently subdividing the tank transversely or zone-wise into two ormore assembly sections each of which maybe loaded and shippedindividually for subsequent complete assembly at the destination, thisbeing in contrast with the heretofore customary type of onepieceapparatus units of much smaller capacity.

Features of this invention lie in the hydraulic water supply anddistributing system for the tank, insofar as it comprises a multitude ofjet-emitting sub-systems each serving a respective cell or teeter bed.Water supply connections or pipes extend from the horizontal jetemittingpipes upwardly within the tank in. each cell to connect with horizontalwater supply headers extending above the tank; characteristically, the.vertical connections or pipes are readily disconnectable from. theirrespective supply headers in such a manner as to enable each re"spective sub-system to be lifted out of the tank after disconnecting itfrom, its overhead, supply header, for inspection or exchange.

According to a more specific feature, since the tank according to. thisinvention consists of transverse rows of square cells or teeter beds,each such row is provided with. an overhead. water supply headertransversely coextensive with ,therow. of cells, and, for each cell apair of vertical supply connections or pipes extends symnietrically downfrom the header, namely. one vertical pipe from each respective side ofthe header.

Each such vertical supply connection or pipe in turn connects at thelower end with a pair of symmetrical branch connections constituting aninverted Y, each branch connection in turn terminating in and connectingwith the middle of the length of ahorizontal jet-emitting distributingpipe which while closed at its ends has extending along its length rowsof jet-emitting orifices or holes. Each such pair of horizontaljetemitting pipes while supported in spaced relationship relative to andby the bottom, is removable from its cell by having the upper end of itsvertical supply pipe disconnected from the header, an adjustableconnection being provided which is not only readily disconnectable butalso capable of adjustably absorbing any changes in the vertical spacingof the horizontal distributing pipes from the bottom. Furtherparticularized, any such change in the vertical spacing of thehorizontal jet-emitting pipes is absorbable by a vertically adjustableor telescoping type of sleeve or flexible hose connection providedbetween the vertical pipe and the header.

According to a more specific feature, the transverse overhead watersupply headers serve as mountings for the automatic density controldevices so that there is no need for any extra bracket or supportingstructures at the top of the tank for any one of the cells. Furtherparticularized, the vertical stem of a spigot valve extends upwardlythrough a vertical passage provided in and through the transverse headerso that valve may thus extend directly into operative connection withthe associated control device mounted atop the header.

The horizontal jet-emitting pipes are provided with a multitude of jetopenings for issuing hydraulic water jets directed at an angle againstthe solid tank bottom to be reflected therefrom, the jet openings andjets beingso arranged relative to one another and so arranged anddirected relative to the bottom that in effect there rises uniformlyfrom the square bottom area of the cell a column of hydraulic watercontrollable and effective to maintain in the cell a correspondingteeter bed. at the desired density. 1

According to still another feature, some or all of the longitudinallyextending submerged partitions are removable so that by means ofwithdrawal or insertion of such partitions a selected area of atransverse classifying zone can be operated with a selected number ofspigot outlets.

In summary, this invention provides a multiple spigot hindered settlingapparatus with a horizontal tank having a narrow inlet-end and a wideoutflow end, in which sequential hindered settling sizing zones comprisea transverse row or rows of submerged cells or teeter beds representingcolumns of substantially equal predetermined square cross-section, eachof which is defined by submerged longitudinal and transverse bafiiewalls disposed at right angles to each other. Each cell or column isserved by its own automatic density-controlled discharge or spigotoutlet valve. Each cell or column also has its own system of horizontaljet-emitting pipes supplied with hydraulic water by a supplysystem oftransversely extending headers through vertical distribution pipesconnected to the header for vertical adjustment.

In the drawings:

Figure 1 is a semi-diagrammatic plan view. of the apparatus unit showingthe tank partitioned into transverse rows of teeter bed cells, with asystem of transverse overhead water supply headers and with densityc'ontrol devices supported thereby.

Figure 2 is a side view of the apparatus unit of Figure 1, with a sidewall portion broken away to show the 6 on line 3*3 in Figure 3, althoughmodified by the addi tion of individual branch pipe control valves inconjunction with flow control orifices.

Figure 4 is a cross-section taken on line 44 of Figure 1 or 2 showing anenlarged and more detailed vertical sectional view of a cell.

Figure 5 is a, perspective view of the interior of the cell of 'Figure4, showing particularly the arrangement of the hydraulic water jetemitting means and illustrating the feature according to which they arereadily disconnectable and removable from the cell.

Figure 6 is a further enlarged detail view of the bottom portion of thecell sectionally shown in Figure l, to illustrate the spatialdisposition of jet-emitting horizontal pipes relative to the cell bottomand relative to one another and the effect of the jets with respect toproducing a uniform upfiow of hydraulic water. 7

Figure 7 is a diagrammatic plan view of the tank stripped of everythingbut the submerged partitions to indicate transverse rows of cells withjet-emitting pipes extending parallel to one another and transversely ofthe tank.

Figure 8 is a diagrammatic plan view of the tank differing from Figure 7with respect to the fact that the jet-emitting horizontal pipes at thecell bottom are disposed parallel to the longitudinal axis of the tank,with some of the longitudinal partitions indicated as being removable.

Figure 9 is a cross-sectional view on line 99 of Figure 8 showingmodified arrangement of supply connections for the jet pipes.

Figure 10 is a detail side view taken on line 10-10 of Figure 6, showingdetails of one of the horizontal jetemitting pipes. 1

The apparatus comprises a tank 10 supported on struc" tural I-beams I,the tank having at the inlet end a feed box F adjoining an end wall E1,and having an end wall E2 provided with a transverse overfiow dischargelaunder D1. The tank has side walls W1 and W2 of stepped configurationas a result of a certain zone-wise subdivision of the tank aspresentlyto be defined. Referring to Figure 7 such a side wall, forinstance W1 then comprises longitudinal plate-like plane portions 11,12, 1s, 14 and transverse or shoulder portions V1, V2, V3. Thus thewidth of the tank increases stepwise from the influent end to theefliuent end, namely from the initial width Y1 to stepwise increasingwidths Y2, Y3, Y4; hence the horizontal bottom B of the tank isdefinable as a plane area consisting of a sequence of rectangularcomponent areas A1=Z1 Y1; A2=Z2 Y2; A3 =Z3XY3; A4=Z4 Y4.

The apparatus comprises the tank 10 subdivided by a system of submergedtransverse partitions p1, p2, p3, p4 into transverse zones Z1, Z2, Z3,Z4 each of which zones in turn comprises one or more transverse rows ofhydraulic classifying cells or columns. Thus the zone Z1 comprises acell C of square area defined by sides S preceded by a cell Co of equalwidth S but of shorter length l. The zone Z2 comprises a singletransverse row of cells C2 and C3 defined by a longitudinal partitionT1. The zone Z3 is shown to comprise a pair of transverse rows of threecells each, namely, a first row of cells C4, C5, C6 defined bylongitudinal partitions T2 and Ta, and a second row of cells C7, C8, C9defined by longitudinal partitions T4 and T5.

The zone Z4 is shown to comprise three transverse rows of four cellseach, namely a first row of cells C10, C11, C12, C13 defined bylongitudinal partitions Ts, T7, Ta, asecond row of cells C14, C15, C16,C17 defined by longitudinal partitions T9, T111, T11, and a third row ofcells C18, C19, C20, C21 defined by longitudinal partitions T12, T13,T14. Advantage is taken of the steppedcontour of the tank unit 10 ofFigure 1, for example by-preparing the tank for shipment in two sectionsZ4 and Z5, and assembling and connecting these sections at the site oferection.

The side wall W is shown to have adischarge launder D2 along the steppedcontour of the wall from point P1 to point P2; the side wall W1 is shownto have a discharge launder D3 along the contour of that wall from pointP3 to point P4. Spouts such as shown at U (Fig. 4) may dischargeoverflowing liquid laterally from the tank into the lateral launders D2and D3.

Each cell has in the bottom thereof a spigot discharge spout 16 fordelivery therethrough of respective groups or fractions of solids calledspigot products resulting from the hindered settling operation in eachcell. The rate of discharge of spigot product is controlled by mechanismwell known of itself, namely a spigot discharge, valve 11 having a valvestem 12 extending upwardly and into operating engagement with anautomatic control relay unit M surrounded and boxed-in by a dot-and-dashline L1 (see Fig. 4) which in turn receives control impulses from aprimary control unit surrounded and boxedin by a dot-and-dash line L2and in turn responsive to variations in the height of a clear watercolumn in a vertical open-ended so-called clear water tube 13. Accordingto this invention each cell is provided independently with suchmechanism for automatically controlling the rate of spigot discharge inresponse to variations in density of a hindered settling column to becontrollably maintained in each cell and resulting from the flow of thesolids suspension passing over the cell in the longitudinal direction ofthe tank in conjunction with the steady upflow of hydraulic controlwater introduced at the bottom of the cell. Hence there are provided(see Fig. 1) for each. of the cells Co through C21 respective controlrelay units Mo and M1 through M21 and respective primary controlnnits O0and 01 through 021, responsive to the variations in liquid level inclear water pipes R0 through R21.

There will now be described the hydraulic water supply and distributingsystem which according to this invention comprises an overhead system ofsupply headers with branch pipes extending from the headers downwardlyinto respective cells to terminate in horizontal water jet-emittingpipes supported upon the bottom in predetermined spaced relationshipthereto and to the walls of the respeclive cells, as well as inpredetermined spaced relationship to one another. The jets are directeddownwardly against the bottom at a predetermined angle which bears asuitable relationship with respect to the distance of the jetemittingpipes from the bottom and the number of jets and their dispositionrelative to one another, so that, there rises from the bottoma flow ofhydraulic water at a rate which issubstantially uniform across the floorarea of the cell, and in effect provides the hydraulic upflow conditionsrequisite for controllably maintaining a teeter bed of the kind that inprior practice was maintained by introducing the hydraulic water througha perforated or so-called constriction plate from a supply chambertherebeneath.

The overhead hydraulic water supply system comprises a horizontal mainsupply header 14 coextensive with the longitudinal extent of the tankand is fed from an overhead gravity tank 14 through a standpipe 14 and acontrol valve 14; the main header'14 has a series of parallel lateralbranch headers extending horizontally transversely of the tank, one suchbranch header to extend over each transverse row of teeter bed cells.Thus, a branch header 15 provided with control valve 15 extends overcell Co; a branch header 16 having a control valve 16 extends over cellC1; a branch header 17 having a control valve 17* extends over cells C2and C3; a branch header 18 having a control valve 18 extends over C4,C5, C6, a branch header 19 having a control valve 19 extends over cellsC7, Ca, Ca; a branch header 20 having a control valve 20 extends overcells C10, C11, C12, C13; a branch header 21 having a control valve 21extends over cells C14, C15, C16, C17; a branch header 22-having acontrol valve 22 extends over cells C18, C19, C20, C21.

All the branch headers are mounted';upo11- and supported bythe sidewalls W1andWz of the tank, for'example as by brackets 23 indicated inFigures 3, 4 and 5. The branch headers in turn support and have mountedthereon the above-mentioned automatic control devices M and O forregulating the rate of spigot discharge.

In this connection, it will be noted that in each cell the stem 12 ofthe spigot outlet valve 11 extends upwardly through a vertical passage24 (see Fig. 5) provided in the associated branch header, so that thestem may conveniently reach therethrough into operative engagement withthe relay control unit M mounted atop the branch header itself.

Each cell receives its supply of hydraulic water from its associatedbranch header by way of a pair of lateral downwardly directed elbows 25and 25 which in turn are each disconnectably connected to vertical pipes26 and 27 by means of respective rubber sleeves or lengths of rubberhose 28 and 29 secured as by clamping rings 28 and 29 respectively. Thevertical pipe 26 terminates at its lower end in a pair of downwardlyinclined branch pipes 30 and 31 constituting with pipe 26 an inverted Y-shape. The inclined branch pipe 30 in turn connects with a horizontaljet-emitting pipe 32 and the inclined branch pipe 31 with a horizontaljet-emitting pipe 33, the horizontal jet-emitting pipes 32 and 33 beingspaced apart from each other a distance d1 and the pipe 32 a distance d2of about /2d1 (see Fig. 6) from the associated vertical partition orwall of the cell. The perspective view of Figure 5 is takensubstantially in the direction of arrow Q in Fig. 1.

Similarly, the vertical pipe 27 terminates at its lower end in a pair ofdownwardly inclined branch pipes 34 and 35 constituting with pipe 27 aninverted Y-shape. The inclined branch pipe 34 in turn connects with ahorizontal jet-emitting pipe 36 and the inclined branch pipe 35 with ahorizontal jet-emitting pipe 37, the horizontal jetemitting pipes 36 and37 being spaced from each other the distance d1 the same as the distancebetween horizontal pipes 32 and 33 and the same as distance d1 beingprovided between horizontal pipes 33 and 36. The horizontal jet-emittingpipes 32, 33, 36, 37 are spaced a distance d3 from bottom B, suchspacing being provided by cradle-like supporting brackets 38 (see Fig.6). Each of the jet-emitting pipes is closed at its ends and has twosymmetrically disposed longitudinal rows of jet orifices, namely a row39 and a row 40 so arranged that the jets from these orifices issue atan angle v against the vertical. The spacing dz between a jet-emittingpipe and the adjacent cell wall is equal to about /zd1 or onehalf of thespacing of the jet-emitting pipes from one another, and the spacings d1,d2, ds and the angle v of direction of the jets all being so related toone another as to produce as a net result and, in effect a flow ofhydraulic water rising from the bottom at a rate which is substantiallyuniform over the floor area of the cell, as jets impinge upon and aredeflected by the bottom as indicated by the pattern of arrows *A" inFigure 6. An effective angle v to produce the desired results is on theorder of 20 against the horizontal for a distance d3 which is on theorder of 1 /2 inches between the jet-emitting pipes and the tank bottom,while the bottom area of a cell may be on the order of 2 /2 feet square.

A transverse stilling or perforated curtain baffle plate K1 (see Figs. 1and 5) is shown to be placed across the horizontal path of the slurrywhere it traverses the partition p1 from zone Z to Zz. The baffle platehas perforations K3 in suitable number and of suitable size, and isdimensioned and positioned in such a manner as to compensate for thehydraulic effects of any such change of flow cross-section as may be duethe stepwise widening of the tank because of the stepped configurationof the side walls of the tank.

In distinction from the Figure 7 diagrammatic plan view, the Figure 8embodiment shows a ditference in the arrangement of horizontaljet-emitting pipes j and it insofar as these pipes are disposed toextend in a direction at right angles to that of the corresponding pipesj and i1 shown in the Figure 7 embodiment, namely in a direction wherebythese pipes are coextensive with the longitudinal axis of the tank, withthe spacing of these pipes from one another being the same as in theFigure 7 embodiment. Another distinction to be noted in the Figure 8embodiment lies in the fact that some of the longitudinal partitions N1as well as the transverse partitions N: are shown to be upwardlyremovable from the tank as by virtue. of guide grooves indicated at G.With component wall portions of the partitioning system thus removablethis Figure 8 embodiment provides a variety of modes of operation whichmake it possible to consolidate operatively into a single teeter bed twoor more cells or columns of a transverse row, or even to thusconsolidate one transverse row of cells with an adjoining row into asingle teeter bed served by a plurality of spigot discharges and spigotdischarge control units. Also, for example in case of failure of thespigot discharge control unit of one cell, a suitable partition may beremoved so that the control unit of the adjoining cell in the row may beemployed to serve both cells constituting a single teeter bed.

If, for example, all of the longitudinal partitions N1 in the last rowof cells be removed as is indicated by the dotand-dash line showing ofthese partitions in Figure 8, there will then present itself a series ofhorizontal jet-emitting pipes j and f1 equidistantly spaced anduninterrupted from side to side of the tank.

The Figure 10 side view of a jet-emitting pipe I shows the pipe tocomprise a pair of end sections J1 and J2 screwed into an invertedT-fitting J3, each section J1 and J2 having at the underside two rows ofjet orifices disposed in a manner similar to the orifices shown inFigure 6. The number and the size of the orifice in a row and theirspacing from one another may differ from transverse row to transverserow of cells because of the differences in hydraulic operatingconditions required to produce the desired solids sizing and classifyingettects upon the slurry as it traverses the rows of cells from influentend to effiuent of the tank.

Figure 3 shows a modification with respect to the vertical branch feedpipes 26 and 27 of Figure 3 and Figure 5 in that a horizontal feedheader 16' has a pair of downwardly extending branch feed pipes 26' and27' each of which is provided with. a control valve 26" and 27"respectively as well as with flow control orifice member 26 and 27respectively. The provision of these additional control means permitseifecting additional and individual control of the rate of flow to becarried steadily by respective vertical branch feed pipes which supplythe jet-emitting horizontal pipes at the bottom of respective sizingcompartments. That is to say, after the branch control valves 26" and27" have been set to provide suitable valve passage area, the orificemembers 26 and 27 will then exercise an automatic control etfect wherebythe rate of flow passing to and through the vertical branch pipes isautomatically maintained at a desired value irrespective of moderatefluctuations of pressure in the branch header 16. That is to say, withinreasonable limits such flow controlling means as the valves 26" and 27"and the orifice members 26 and 27 interposed in the respective branchfeed pipes 26 and 27' will serve to maintain substantially constant adesired rate of flow in the branch pipes even though pressure conditionsin the supply header might vary.

Operation In the operation of this apparatus the feed of slurry to besubjected to classification treatment passes from feedbox F where itreceives diluting water if necessary, over I the submerged feedpartition fo across a preliminary cell Co where the rate of upflow ofhydraulic water issuing in the form of jets from jet-emitting pipes i1is adjusted by means of valve 159. to have an 'upfiow' intensitysufiicient to permit ,substantially the largest size only to beintercepted while the density of the teeter bedrequisite for efiectingsuch selective interception is automatically maintained by the spigotdischarge control units M0 and O0 in conjunction with clear water pipeRu. That is to say, as the density in the teeter bed varies it willproduce corresponding variations of liquid level in the clear water pipeand these variations in turn will by their hydraulic pressure variationsinfluence the primary control unit 00 which in turn actuates the relaycontrol unit Mo adjusting the spigot discharge valve 11 to allow theescape of a quantity of solids sufiicient to restore the density of theteeter bed as maintained by the upflow of the hydraulic water suppliedat the bottom of the bed. In other Words if the density is too great thespigot valve will rise sufficiently to reduce the density and if thedensity is too low the spigot valve will lower sufliciently to effectupward correction of the density.

The flow of slurry minus the coarsest size solids continues horizontallyacross the submerged partition po and across cell C1 where again a lesscoarse fraction of solids is intercepted and is isolated from the slurryby establishing and maintaining in the cell the requisite density of theteeter bed therein, such density being automatically maintained as bythe rate of hydraulic water supply through control valve 16a inconjunction with automatic control of spigot discharge from that cell bymeans of the primary control unit 01 and a relay control unit M1responsive to the liquid level fluctuations in the clear water pipe R1.The slurry minus the solids fraction as presented by the spigotdischarge from cell C1 continues across the transverse partition p1while fanning out over the zone Z2 (that is area i2 y2) comprising cellsC2 and C where again a density of the teeter beds is maintained in theteeter beds therein requisite to produce from them spigot dischargeproducts which represent the next smaller size fraction of solidsdesired, the density of these teeter beds and the spigot dischargeproducts therefrom being controlled by the rate of hydraulic watersupply from control valve 17 coupled with the control function of thespigot discharge control units M2 and O2 and of clear water pipe R2, andof spigot discharge control units M3 and 03 with their clear water pipeRs.

The slurry minus the spigot discharge products from cells C2 and C3 thencontinues across the transverse partitions p2 and p3 fanning out overthe zone Z3 (i. e. area i3 y3) comprising the two rows of cells C4, C5,C6, and C7, C8, C9 respectively. Again the next smaller size solidsfraction selectively intercepted from the slurry by these cells isobtainable by way of the spigot discharge products from the cells C4,C5, C6 being regulated by their re spective spigot discharge controlunits M4, M5, M6 and O4, O5, 06 with their respective clear water pipesR4, R5, R6, the cells being supplied with the requisite amount ofhydraulic Water through control valve 18 The operation of the second rowof cells C7, C8, C9 of zone Z3 is similarly conducted and controlled tohave them yield a classified spigot discharge product representing thenext smaller size fraction of the solids.

Again the stream of slurry minus the preceding spigot discharge productsfans out across the transverse partition p4 then further acrosstransverse partitions 125, pa in zone Z4 (i. e. area i4 y4). The nextsmaller size solids fraction is thus selectively obtained by way of thespigot discharge products from the first transverse row of cells C10,C11, C12, C13 in zone Z4, the next following smaller size fraction isobtained by way of the spigot discharge products from the secondtransverse row of cells C14, C15, C16 of zone Z4. while the last andsmallest size fraction is selectively obtainable by way of these spigotdischarge products of the third transverse row of cells C17, C13, C19 ofzone Z4, whence the carrier liquid of the slurry containing residualfines may pass from the tank by overflowing into the efiluent launderD1. The requisite teeter bed densities in the respective transverse rowsof cells in zone Z4 and the desired size spigot discharge, products fromthe respective rows are controllably obtainable in a manner similar tothat described for the preceding zones Z1, Z2, Z3, namely by means ofsuitable rates of hydraulic water supply through the control valves 2021*, 22 in conjunction with automatic spigot discharge control by therespective control units for the respective cells.

Figure 9 resembles Figure 3 except for the fact that it providesvertical branch feed pipes 4-1 and 42 leading directly oif the undersideof the associated horizontal transverse water supply header, thevertical branch pipes being provided with disconnectable sleeves 43 and44, each vertical branch pipe to supply its pair of horizontaljet-emitting pipes jz.

The desired uniform rate of hydraulic water rising from the fioor of therespective cells is attainable by proper correlation of the spacing ofthe jet-emitting pipes from one another and from the number, size anddisposition of the jets issuing from these pipes, and the verticalspacing of the pipes from the cell bot-tom. For example, for a givenequidistant horizontal spacing of the pipes and given number, size anddisposition of the jet holes, the desired uniform upward flow effect maybe attained by adjusting the vertical spacing of the pipes. relative tothe tank bottom as by a change of brackets 38. When difierent operatingrequirements call for a change in the size, or number or disposition ofthe jet orifices, the vertical branch feed pipes may be disconnected byunfastening their respective sleeve or similar connections, removingthem, unscrewing the horizontal end sections it and i2 and replacingthem with substitute sections having for example different size jetorifices, then re-inserting them in respective cells and reconnectingthem with their respective transverse supply headers.

I claim:

1. A hindered settling apparatus having a tank providing a horizontalsequence of solids-classifying zones of respectively increasing averagewidth in which a liquidsolids feed mixture carrying a Wide range ofsolids sizes from coarse to fines, in passing sequentially in ahorizontal stream over said zones from the narrow influent zone to thewide efiiuent zone is classified into intermediate size ranges issuingas spigot products from the bottom of respective zones, while a teeterbed is maintained at a desired density in each zone by supply meansproviding a controlled upflow of hydraulic water therein as well as bycorrective control of a spigot outlet valve, and in which automaticdensity-responsive control devices are provided for each zone for socorrectively actuating the spigot outlet valve as to automaticallymaintain said desired density; characterized thereby that the tank isprovided with a submerged system of longitudinal partitions at rightangles to said transverse partitions and disposed to subdivide the spacebetween each pair of transverse partitions into a transverse row ofcolumnar cells of substantially square cross-section and ofsubstantially identical size, so that the infiuent end of the tankcomprises a single initial such cell whereas the effluent end portioncomprises a multiplicity of such cells in a transverse row, each saidclassifying zone having one more cell than the preceding zone so thateach side wall of the tank presents a plan view of stepped lateralcontour with both contours being substantially symmetrical to each otherand each step of each contour being the equivalent substantially ofone-half of thewidth of. a cell, with the addition of hydraulicoperating water supply means comprising a plurality of stationaryhorizontal pipes substantially rectilinear and parallel to each other,each pipe having along each side thereof a row of orifices disposed foremitting jets of operating water obliquely towards the tank bottom, yetin a direction substantially perpendicular to the longitudinal axis ofthe pipe, overhead conduit means for supplying operating water,downwardly extending branch conduit means connecting said overhead meanswith said horizontal jet-emitting pipes, control means for regulatingthe supply of operating water to said jet-emitting pipes, the number ofsaid jet-emitting pipes, their spacing with respect to one another, aswell as. with respect to the boundaries of respective cells, and thenumber of jets issuing from each pipe and their angle of incidencerelative to the bottom, and the volume of water supplied to the jetsbeing such that there is obtainable in effect an upflow of operatingwater from the bottom substan-. tially uniform across the cell, withsaid water control means as well as said automatic density-responsivecontrol devices being independently settable with respect to each otherfor maintaining a desired density in respective cells whereby to obtaindesired size fractions from respective transverse rows of cells.

2. Apparatus according to claim 1, in which said branch conduit meansare provided with disconnectible pipe connecting means for effectingvertical adjustment of the jet emitting pipes relative to the, bottomand relative to the overhead conduit means, with the addition of bottomsupports defining the distance between the jet emitting pipes from thetank bottom.

3. Apparatus according to claim 1, in which the water supply means forone transverse row of cells comprise an overhead supply headercoextensive with said row, and the branch conduits comprise for eachcell of said row a pair of branch conduits disposed to straddle thespigot valve, each branch conduit in turn terminating at its lower endin a pair of branches constituting an inverted Y-shape with thehorizontal jet emitting pipe being provided for and connectingsubstantially at its middle to the end of a respective branch of saidinverted Y-shape, with the addition of bottom supports defining thedistance between the jet emitting pipes and the bottom, with a pair ofsuch pipes disposed at each side of the spigot valve and with thefurther addition of disconnectible pipe connecting means between eachbranch conduit and said header.

4. Apparatus according to claim 1, in which said branch conduit meansare provided with disconnectable, flexible tube connections foreffecting vertical adjustment of the jet emitting pipes relative to thebottom and relative to the header, with the addition of botom supportsdefining the distance between the jet emitting pipes and the bottom.

5. Apparatus according to claim 1, in which the water supply means forone transverse row of cells comprise an overhead supply header centrallycoextensive with said row, and the branch conduit means for a cellcomprise a pair of lateral downward pipe elbows extending symmetricallyfrom respective opposite sides of said header, a vertical branch pipefor each elbow, each vertical pipe having at their lower end a pair ofbranch connections constituting an inverted Y-shape disposed in a planeextending transverse of the header, with a horizontal jet emitting pipebeing connected at their middle to the end of each branch of saidinverted Y-shape and thus being disposed substantially coextensive withsaid header, so that a pair of such jet emitting pipes is disposed ateach side of the spigot valve, and disconnectable pipe connecting meansbetween each elbow and its respective vertical pipe.

6. Apparatus according to claim 1, in which the water supply means forone transverse row of cells comprise an overhead supply headercoextensive with said row, with the addition of mounted means providedupon said header for supporting thereon the respective densityresponsive control device for respective cells.

References Cited in the file of this patent UNITED STATES PATENTS

